Machine for cold-rolling.



No. 63|,I5,9. Patented Aug. I5, |899. F. G. ECHOLS.

MACHINE FOR COLD ROLLING.

(Application filed Nev. 4, 189B.) (No Model.) 3 Sheet-Sheet l.

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.IIIIIIII IIIIII' In vena/'f Patented Aug.A I5, |899.y F. G. ECHOLS.

MACHINE FOB COLD ROLLING.

(Application led Nov. 4, 1898.)

3 Sheets-Sheet 2,

(No Model.)

No, ma@ mm e o EM a.. I

Patented Aug. l5, |899.

F. G. ECHULS.

MACHINE FOR COLD ROLLING.

(Application led Nov. 4, 1898 1 3 eats-Sheet 3.

(No Model.)

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1o rolling to a precisionized form threads cut in t PATENT FRANK G.ECHOLS, OF HARTFORD, CONNECTICUT.

ll'viA'oi-HNE FOR COLD-ROLLING.

SPECIFICATION 'forming part of Letters Patent No. 631,1 59, dated August15, 189e.

` tipping-.tion flied Nwemtei, 189s. serial No. 695,431. (No modem To@ZZ 1,071,011@ t may concern:

Be it known that I, FRANK G. EoHoLs,a citizen of the United States,residing in Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inMachines for' Cold-Rolling Screw-Threads, of which the following is aspecification.

My invention relates to machines for coldother kinds of thread or withslight modifi-1 cations in the manufacture ofvarious tools or objects ofmetal in which accurate and hardened working faces are essential.

In the usual practice of cold-rolling a screwthread directly upon a barof metal what is termed the skin of the material is not removed, andsaid skin, which is quite thin, is

so affected bythe cold-rolling operation that the thread will Abecomewarped or distorted' during the process of tempering, thereby seriouslyweakening the surface or cutting edge of the article and also materiallyimpairing its quality of precision. In my improved process, however, theprimary cutting of the thread or surface of the metal removes this weakskin, and the blank is therefore in better condition for the subsequentrolling operation by which the molecules. of metal are fio compactedinto a solid and dense mass, the

result being that the Working surface of an article produced in 'thismanner will not become distorted or warped while being tempered and thatthe finished article will be in as nearly a precisionized form as can besecured mechanically.

My improved machine comprises one or more thread-forming rolls, whichare prefer'- ably rotatably supported, and in the present 5o case tworolls are represented, mechanical means being employed for sustainingthe blank while it is being subjected to the rolling operation. Theserolls are duplicates, and

they should be of substantially the same diameter, so that they willuniformly rotate, and said rolls are preferably mounted for yieldingmovement longitudinally, whereby the threads upon the periphery thereofmay automatically lind or seat themselves in the grooves between thethreads of the blank.

In the drawings accompanying and forming part of this specification,Figure l is a plan View of my ,invention shown as applied to an ordinaryturning-lathe. Fig. 2 is a horizontal plan view, partly in section,showing the rolls in operation upon a blank with cut threads thereon.Fig. 3 is a side view showing a blank supported between the centers ofthe lathe and illustrating an attachment by which the position of therolls with relation to said blank may be accurately determined. Fig. 4is a vertical section taken on line .fr of Fig. 2.y Fig. 5 is a view ofthe blank with' a cut thread before it has been coldrolled. Fig. Gisa'view of the finished blank having a cut thread cold-rolled. Fig. 7 isa detail view in section, showing the action of one of the rolls uponthe blank. Fig. 8 is a diagrammatic view, on an enlarged scale, showingthe 'same action,and Fig. 9 is a diagrammatic view showing by dottedlines the original form of the thread and by stippling the changesinform and in the densitication of the metal during the cold-rollingoperation.

Similar characters designate like parts in all the figures of thedrawings.

For convenience in demonstrating the nature of my invention I haveillustrated the same applied to a metal-turning lathe of ordinaryconstruction, in which case the blank to be operated upon ismountedbetween the head and tail centers of said lathe, although it isobvious that the invention is not limited to the character of meansshown for supporting the same, it being adapted for` use with variousclasses of machines.

The lathe includes the usual live and dead centers 2 and 3, betweenwhich the blank, as B, is supported, and as I prefer to rotate saidblank while cold-rolling the same the necessary motion is transmittedthereto from the live spindle or center 2 through the faceplate 4 anddog 5. It is evident that the IOC blank B, which is illust-rated as atap-blank, may be otherwise supported by the lathe and also differentlyrotated, and also that the blank may be held stationary and the rolls becaused to revolve around and travel along the same, if deemed desirable.r1`he driving mechanism for the live-center is designated in a generalway by D.

As hereinbefore set forth, my improved machine includes means forcold-rolling the surface of a previously-cut blank, said blank beingshown as a threaded one,and to accomplish this purpose two rolls areillustrated, they being designated by R and R and conveniently carriedby section 41 of the slide S, which travels along said slide as therolling operation progresses, the blank being rotated and its threadserving by its engagement with the threads of the rolls to advance saidslide-section 41 longitudinally of the blank.

I have found in practice that by my improved mode of operation a tap isproduced the thread of which is of precisionized form and the moleculesof metal constituting said thread are Wrought together or swaged into acompact condition, the result being a finished article having a uniformand perfect thread, which has long been a great desideratum.

After the blank with a out thread has been operated upon by the rolls itis to be grooved or fluted and then tempered, and in virtue of thecold-rolling operation the metal near the periphery of the blank is sodense and compact lthat it will not become materially warped ordistorted when the tap is subjected to the hardening process.

The rolls R and R' have surfaces adapted for cold-rolling the truncatedout thread of the blank and for finishing the saine, and said rolls areground with great accuracy, whereby the reproduction of the form of thethread thereof on the tap-surface is as near precision as can beobtained. The rolls are rotatively mounted in the blocks 12 and 13,supported for sliding movement in the transverse bore or passage 14 inthe section 41 of slide S and therefore may be moved toward or from eachother, said rolls being shown journaled on the shafts 15 and 16, fixedin bearings inthe two blocks. In working upon blanks of, a uniform sizethe roll R is usually held in fixed relation, while the companion roll Ris moved toward or from the same, either to act upon the blank or permitthe removal of the same.

To produce work of differing diameters, the block 13, carrying roll R',may be moved inward or outward, as the case may be, to accommodate thesize of blank to be rolled. The roll-carrying blocks 12 and 13 are slidback and forth in the bore 14 by the screws 2O and 21, which passthrough the fixed nuts 22, fitted in the opposite ends of said bore. Asbefore stated, the block 13 is normally maintained in fixed relation tothe complemental block, and for thus holding the saine a check-nut 23,in threaded engagement with the screw 21 and abutting against the fixednut 22, is employed.

The screw 2O is equipped with a crank 24, by which it maybe turned toadj usttheblock 12, and hence the roll R, toward or from the blank.

To enable the roll R to be accurately reset after a finished blank hasbeen removed and an unfinished one placed in position, there is employedin connection with said roll an index or gage, which is preferablycarried by the screw 2O and which consists in the present instance of adisk graduated in thousandths of an inch, whereby accuracy in thereadjstment of said roll is insured. This index is illustrated as a diskG, which is fixed to screw 20, said disk being graduated, as at 30, andthe graduations being adapted to cooperate with the gage or index-mark31 upon the outer surface of the slide-section 41 in proximity to theperiphery of the disk.

In Fig. 2 the rolls R and R' are shown operating upon the blank B, andin-Fg. 3 the parts are represented occupying a corresponding position,the index-mark O being opposite the mark 31 upon said slide-section.Then the rolling operation is completed, the crank 24 is turned,therebycausing the screw 2O to move the block 12, and consequently theroll R, away from the work, so that the latter can be removed from themachine, and when a new blank of the same diameter is placed in positionthe crank is turned in a reverse direction until the zeromark is broughtopposite or'in line with said mark 3l,7 thereby indicating that theblock 12 is in correct position-fi. e., the one it before occupied. Inadjusting the roll R to a blank of a different diameter the zero-markwill of course be opposite another index, the relation shown beingmerely to illustrate the nature of the gage.

In Fig. 5 I have illustrated a blank D' having threads cut thereon inthe usual manner, while the blank with the finished and precisionizedcold-rolled thread is designated by B in Fig. 6. To cold-roll the blankB', it is first mounted between the centers 2 and 3 of the lathe, theslide S being in such a position that the normally stationary roll R' isclear of and is opposite an extreme end of said blank, the roll R beingralso out of contact with the blank and opposite said roll R. The slide Sis then moved until the thread of the roll R' is opposite the cut threadon the blank, after which the crank 24 is manipulated to cause thethread of said roll R to enter the grooves between the convolutions ofthe thread of the blank at a point directly opposite the roll R', thisrelation of the parts being represented in Fig. 4. The spindle 2 is thenset in motion, and as the blank turns the threads thereof will rotatethe rolls R and R', and as these rolls rotate the upper section 41 ofthe slide will of course be moved toward the shank 42 of the blank, thesaid rolls as IOO IIO

they turn cold-rolling the cut thread to finish and precisionize thesame. When the blank has been cold-rolled, it is in the conditionillustrated in Fig. 6, and to remove the same from between the twocenters the crank 24 is first turned to carry the roll R away from saidl blank, and subsequently the slide section 41 is manipulated to carrythe threads of the roll R' beyond the periphery of the rolled blank. Thetwo rolls R and R' are of substantially the same size, and their outsidediameters are the same throughout the length thereof, and the bottoms orbases of the threads of said rolls are of the same width; but .thewidths of the tops or apeXes of said threads gradually increase froma Vshape in the rst convolution to a truncated form, the several threads(see Fig. 7) being designated, respectively, by a, b, c, d, and e, andthe two firstmentioned ones being angular, while the three succeedingthreads are of progressively-increased widths at their truncatedportions.

The blank B has comparatively wide truncated cut threads, saidthreads-bein g reduced to the desired standard, and the diameter of theblank being increased slightly by the coldrolling operation.

On inspection of Figs. 7 and 8 it will be observed that the firstconvolution a of the roll thread displaces the adjacent convolution ofthe cut thread of the blank toward the longitudinal axis thereof and atthe same time radially outward and that the next convolution h reducesthe thread of the blank to a still greater degree, this operationcontinuing until the thread has reached the requisite standard at thetime it leaves the last convolution e of the roll. The apeXes of theseveral convolutions of the thread of the blank are at first caused toassume a slightly concave form by the rolling operation; but this iswholly eliminated by the contact of said convolutions with the bottomsof the grooves of the nishing threads of the rolls, as shown in Figs. 7and 8. The rolling operation successively densities or compacts themetal and forces the same radially outward, the stippling in Fig. 7 ofthe successive convolulions of the blank B showing the manner in whichthe molecules of the metal are compressed. This 4peculiarity is alsoillustrated in Fig. 9, the dotted line a indicating aconvolution of thecut thread before it reaches the rolls R R', and the lines b', c', cl',and e indicating the respective compressions of the molecules of themetal by the rolls, and the blank space between the lines d and e'indicating the condition of the metal at the last step of the operation.

For the purpose of seating the threads of the rolls R and R without thenecessity of adjusting the slide S or the bl'ankrwith relation to saidrolls I prefer to make one or both of the latter yielding inalongitudinal direction.

The shafts or pins 15 and 16 are mounted in the present case for slightmovement in the direction of their axes in their bearings in the bricks12 and 13, and said Shafts 15 and 16 are encircled near their oppositeendsthat is, between the rollers and their bearings-by springs, as 45,(see Figs. 2 and 4,) which bear against the blocks and the rolls,respectively,to hold the latter substantially midway between thebranches of said bearings.

In positioning the roll R' with respect to the work the thread of saidroll may squarely strike the thread of the blank, and as said roll isadvanced the beveled surface of the cut thread of the blank, actingagainst the corresponding surface of the roll thread, acts as a wedgeand moves the roll in the direction of its length, so that the thread ofthe roll can be accurately seated in the grooves of the blank, the rollR being capable of the same operation. It will be observed that the axesof the rolls are parallel with that of the blank, and for the purpose ofadjusting the rolls to enable them to operate on threads of varyinginclinations they are mounted for shifting movement relatively to theblank and independently of the rotative and longitudinal movementshereinbefore mentioned. This adjustment for-effecting different degreesof angularity may be obtained by supporting the rolls for bodilyshifting movement in a plane transverse to the plane of the axis of theblank and is carried outv as follows: The blocks 12 and 13, whichconstitute convenient carriers for the two rolls, are

preferably made cylindrical to conform to and turn in the bore orpassage 14 in the slide. Should a blank having threads of differentinclination from that represented in Fig. 5 be inserted between thelathe-centers, the rolls will automatically adj ust themselves to saidthread, the two blocks rotating in-their seats and the threads of therolls instantly seating themselves in the grooves of the'blank.. The twoblocks 12 and 13 are connected with the screws 2O and 21, respectively,by couplings which permit the rotative movement of said blocks aroundthe screws, the latter terminatin g at their inner ends in enlargedheads 50 and 51, fitting against plugs 52 and 53,'16- spectively, whichare seated in the louter faces of said blocks. Flanged caps, as 54 and55, secured by screws or other suitable means to the blocks, hold theheads 50 and 51 in place. Bytheconnectionsdescribedbetween thefeed-screws and the blocks said screws may be rotated to move the blocksin opposite directions, and the blocks may also rotate independently ofthe screws to adapt the rolls to threads of different inclinations.

No claims are herein made to the metalworking tool or to the method ofmaking said tool, said method and article constituting thesubject-matter claimed in my contemporaneously-pending application filedNovember 4, 1898, Serial No. 695,430.

Having thus described my invention,what I claim, and desire to secure byLetters Patent, is-

1. In a metal-working machine, the combi- IOO IIO

nation, with means for supporting a blank having a cut thread thereon,of means for cold-rolling said thread.

2. In a metal-working machine, the combination, with means forsupporting a blank having a cut thread thereon, of means forcold-rolling said thread to precisionize the same; and means forrotating one of said parts relatively to the other.

In a metal-working lnachine, the combination, with means for supportinga blank having a cut thread thereon, of means for cold-rolling saidthread to precisionize the same; and means for rotating theblank-supporting means.

4. In a metal-working machine, the combination, with means forsupporting a blank having a out thread thereon, of rolls having accuratethreaded surfaces for cold-rolling said cut thread to a precisionizedform of standard size and gage.

5. In a metal-working machine, the combination, with means forsupporting a blank having a thread formed by cutting or removin g themetal, of rolls having accurate threaded surfaces for cold-rolling saidthread to a precisionized form of standard size and finish, one of saidrolls being movable toward and from the blank.

6. In a metal-working machine, the combination,witl1 live and deadcenters for supporting a blank having a cut thread, of a slide;

and a pair of rolls mounted upon the slide, said rolls havingaccurately-shaped, threaded surfaces for cold-rolling the cut threads toa precisionized form.

7. In a metal-working machine, the combination, with means forsupporting a blank having a out thread, of a pair of rolls each havingaccurately-formed threaded surfaces adapted to act upon said cut threadand coldroll the same to a precisionized form, said rolls beingeachsupported forlongitudinallyyielding movement, whereby the threads on thesame will automatically seat themselves in the groove between thethreads of the blank.

S. In a metal-working machine, the combination, with means forsustaining a blank, of a support; a pair of threaded rolls looselymounted in said support and adapted to act upon the blank; and springsacting against both ends of each roll, said springs permitting the rollsto yield longitudinallyin either direction.

9. In a metal-working machine, the combination, with means forsupporting a blank, of a threaded roll for rolling a thread previouslyformed on said blank, said roll being shiftably supported automaticallyto adapt itself to threads of various inclinations.

10. In a metal-workin g machine, the combination, with means forsupporting a threaded blank, of a threaded roll for rolling the threadof said blank and shiftably supported automatically to adapt itself tothreads of various inclinations; and a feed-screw connected to, andmovable independently of, the roll.

11. In a metal-working machine, the combination, with means forsustaining a blank, of a support; a roll having a threaded surface; anda carrier for the roll loosely mounted in said support and free to moveautomatically therein.

12. A metalworking machine including means for cold-rolling the surfaceof a blank having a cut thread-said means consisting of a roll and acooperating surface having threads of accurate form which act upon thecut threads of the blank and reduce the same by cold-rolling to aprecisionized standard gage, substantially as and for the purposespecified.

13. In a machine of the class specified, the combination, with means forsupporting a blank, of a threaded roll in engagement with one side of ablank; a threaded surface in engagement with the other side of saidblank; a support for said roll and threaded surface, said support beingmovable longitudinally of the blank; a roll-carrier capable of automaticmovement in the support to present the roll at the desired angle to theblank; and means for adjusting the roll toward and from the blank.

14. The combination, with a set of rolls, of a cylindrical supportforeach of said rolls and in which they roll is loosely mounted; andsprings bearing against each side of the roll, the construction beingsuch that the roll is permitted to have a yielding movement transverselyof its support.

15. In a machine of the class specified, the combination, with the liveand dead centers of a lathe adapted to sustain a blank between them, ofa slide on the lathe-bed and movable longitudinally thereof; a carriermounted for reciprocating movement transversely of said slide; rollsyieldingly mounted in said carrier to have angular adjustment therein;and springs bearing against the sides of each roll.

16. The combination, with the live and dead centers of a lathe, of aslide mounted for longitudinal movement on the lathe-bed; a carriermovable transverselywith relation to said slide; cylindrical supportsmounted for rotative movement in said carrier; rolls mounted on pinscarried by said supports; and springs pressing against each side of therolls Whereby they are permitted to have a limited amount of movement.

17. In combination with the live and dead centers of a lathe, a set ofrolls having threaded peripheries and mounted for both longitudinal andtransverse adjustment between said centers; means for yieldinglysupporting said rolls; a screw for adjusting one of said rolls withreference to the other roll; and a gage for indicating the amount ofadjustment of the roll.

FRANK G. ECIIOLS.

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